Grid



June 27, 1944.

w. .J. KNOCHEL ET AL 2,352,203

\ GRID Filed March 12, 1943 a5 T 42 33 17, I "i 21 a J5 I 1 gr mi V;

INVENTORS WJT KNOCfi/EL J GONE.

ATTORNEY Patented June 27, 1944 GRID William J. Knochel, East Orange, and James H.

Cone, Mntclair','N; J., assignors to Westinghouse Electric '& Man

ufacturing Company, East Pittsburgh, Pa.,-a corporation of Pennsylvania 7 Application March 12, 1943, Serial No. 478,890

" '7 Claims;

devices, and moreparticularly to grid structure and mounting of. the same and associated parts.

In general, the present invention is an im provement .upon thestructure disclosed in prior Patent 2,229,050'issued. January 21, 1941, 130 the same assignee as the present application. l? loth manufacturing and operating diiiiculties have been encountered inconnection with suppressor grids heretofore employed in electronv discharge devices of the character of the said prior patent. In practice, asuppressor grid. having an end band continuous .in cross section has been found impractical to make, asa result of which the commercial embodimentsof the prior patent showing have been made .with the band fabricated from a strip of metal the ends whereof were caused to overlap along one of the extended parts of the grid structure .and welded together at the overlapping areas. Grids so made, however, proved unsatisfactory in .use, the primary difficulty then developingof distortion of the band, the distortion generally occurring as a bulge of the entire extendedpart of the band instead of that part remaining flat. To eliminate that trouble and increase production attempt was made to substitute close winding of the grid wires in substitution for the band, but again it wasfound the structure bulged and manufacturing shrinkage due. to the unsatisfactory proportion of devices wasibeyond reason. The present invention accordingly is directed to overcoming thedifiiculties and unsatisfactory arrangements of the prior art.

Generally expressed, therefore, an object of the invention is to provide a grid band which will have and retain extended flat areas.

Of the same general, nature, an object of the invention isto provide grid bands which may be fabricated to precise shape before mounting in position in the device or on the supporting'posts therefor. v

Another object of the invention is to enable the grid band to be readily and accurately made by punched parts. I

A further object of the invention is to obtain fabrication of the grid band from a plurality of identical parts which can be readily assembled without any distorting stresses inherent therein or introduced during fabrication.

Still further objects of the invention will appear as the description progresses, both by direct recitation thereof and by implication fro n the context.

Referring to the accompanying drawing in (01. 250-275) This invention relates to electron discharge:

which like numerals of reference indicate similar parts throughout the several views;

Figure 1 is an elevation of an electron discharge device embodying the present invention and shown with a part of the envelope broken away for better illustration of the structural parts therein;

Figure 2 is averticalsectional view of the upper portion of the electrode assembly but with the inner electrodes in elevation;

Figure 3 is a sectional-plan substantially on line III-III of Fig. 2 I I Figure 4 is an edge view, substantially on line IVIV of Fig. 2, and showing a part of the suppressor .grid band in section; and I Figure 5 is a perspective viewv of the grid-band sections before assembly and in proximity to the posts to which they are tobe attached.

In the specific-embodiment of they invention illustrated in said drawing, the general tube structure is in conformity with the corresponding parts shown and described in the said prior Patent 2,229,050. Briefly reviewed, the general assembly comprisesa glass envelope Ill carried at its lower end in a base I I and having at its lower end as a sealed part of the envelope a re-entrant stem l2 and press 13 through which a part'of the electrode connections are sealed. [Around .a part of thestemis a clampcollar l4 to which are secured upwardly extending supporting rods l5. Somewhat abovethe press I3 is located a transverse lower insulator or spacer I6 rigidly carried by said rods which project through edge margins of said insulator, and at the top of said rods is another insulator or spacer ll similar and parallel to the first and also rigidly carried by said rods. The several electrodes, described hereinafter, are all between these two spacer insulators and thereby.

The outermost electrode is here shown as an anode I8 spaced inwardly away from said rods and supportedby longitudinal anode-supporting rods is parallel to and between pairs of the insulator supporting rods l5. The top and bottom ends of the anode are parallel'to and spaced from the lower and upper said insulator spacers l8, l7 and held rigid with respect theretoby sleeves 2!] on the anode rods. Said anode rods extend above the upper insulator and have a conductive bridge 2| connecting them and in turn connected by 'leadfl22 to' a cap terminal 23 at theoutside of the envelope. The anode is a hollow structure; preferably carbon, with an even inner surface, having the general form of exare directly'or indirectly carried.

of the suppressor tended front and back faces and semicylindrical side faces connecting the same as a continuous anode area.

Spaced within the anode and in parallelism to the inner surface thereof and spaced therefrom is a suppressor grid 24 the construction whereof is a feature of the present invention and will be described more at length hereinafter. For present purposes suflice it to say that said grid is carried by posts or rods 25 within the opposite curved sides thereof and which extend through the insulator spacers l6 and I1 for support at their opposite ends. The lower ends of these rods 25 project below-the lower spacer and have a transverse metallic shield 26 attached thereto, said shield overlying the end of the stem and press.

Next within the suppressor grid 24 is a similarly shaped but smaller screen grid 21 in parallelism to the anode and suppressor grid and provided with longitudinal roots or posts 28 within the curved side walls. These rods 28 likewise extend through the two spacer insulators above described so as to be positioned and supported thereby. One of these rods may conveniently be utilized as a lead-in connection.

Next within the screen grid is shown a similar- 1y shaped but smaller control grid 30 in parallelism to the anode, suppressor grid and screen grid and provided'with longitudinal rods or posts 3| within the curved side walls. Theserods 3| extend downwardly through the lower insulator spacer for support and lead-in purposes, but do not extend to the upper insulator spacer. Instead, they are supported by projecting through an auxiliary insulator spacer 32 somewhat below and parallel to the upper insulator spacer and of smaller size so as to have a position within the confines of the suppressor grid 24. Support for this auxiliary insulator spacer is accomplished from the suppressor grid which has appropriate holes therethrough for passage of the rods 28 by which the screen grid 21 is supported to enable those rods to extend through the auxiliary insulator spacer to the upper one.

A usual or any desired type of cathode 33 is provided within the control grid, the present showing indicating said cathode to be of M formation with the upper bights thereof below the auxiliary insulator spacer and carried by hooks 34 the shanks whereof extend upwardly through holes in both insulators thereaboveand supported by springs or tensioning means 35 above the upper insulator spacer. Appropriate lead-in wires 36 are provided at the bottoms of the legs of the M-shaped cathode in accordance with usual practice. 7

Returning now to a more detailed description grid, the same is preferably constructed to have an impervious band 31 terminating the upper end of thegrid body and a similar impervious band 31 terminating the lower end of the grid body. The body of the grid between these bands is formed as a flattened helix of Wire.

the grid is welded to the posts thereby forming the complete grid. Both bands are constructed identically, so a description of one will suffice for both.

I Said band 31 is fabricated as a pair of stamped metallic sections or strips 38 assembled end to end with one section 38 complementary to the other. Each section has its major portion substantially flat thereby providing an extended flat area. The end portions of the strip or section curls at 39 to a direction substantially perpendicular to the extended flat area. The curled ends of one section are formed to inter-engage with the curled end of the other section but without protrusion over the face of the strip. As here shown, each strip has a mortise-like notch or recession 40 in one end and a. corresponding tongue or projection 4| of tenon-like form projecting from the other end. As both sections are identical, the tongue of one section may be inserted in the notch of the other section while the notch and tongue at the other ends are appearing in section as a Each convolution of the wire forming structure described, the section and the strip material next the notch similarly interengaging. consequential upon the tongue at the end of one of the other section will form a continuity of surface. By virtue of this continuity of surface, the supporting rod may be juxtaposed to the tongue of the one section and the adjacent part of the other section thereby enabling both sections to be welded to the rod directly. Furthermore, the interengag'ement of the tongues in the notches assures location of the top edges of both sections in a common plane and furthermore is an assistance to the operator for speedily and accurately assembling and welding the sections on the posts.

In order to support and accurately position the auxiliary insulator spacer 32 and at the same time adequately shield the control electrode, a metallic electrostatic shield 42 is provided between the upper insulator spacer I1 and the auxiliary spacer 32. Preferably this electrostatic shield is assembled with the auxiliary spacer before those parts, are assembled, as a unit, with the electrodes. In order to accomplish the subassembly of the two parts mentioned, the shield has end tabs 43 depending therefrom which pass through holes for the purpose close to the ends of the insulator spacer, said tabs being bent outwardly under the spacer after passing through the holes and then up at the outside of the spacer and inwardly at the top thereof. .Except for the engagement of the tabs with the spacer, the shieldis otherwise spaced away from the spacer and avoids shorting with respect to the electrodes. or their supporting rods.

It is desirable to mount said electrostatic shield 42 accurately in position and parallel to the upper edge of the upper band of the suppressor grid. This desideratum is accomplished by providing longitudinal up-standing flanges 44 at the long edges of the shield, said flanges being parallel and spaced from each other a distance equal to the spacing of the extended flat faces of the band 31 so as to fit nicely within the band with the flanges juxtaposed to the contiguous parts of the flat faces of the band. The material forming the flanges is bent outwardly and downward, as at 45, hook, but as this hooked edge is coextensive with the length of the flange, it provides a long trough and a long engagement with the upper edge of the band. As the bending of the flange is accomplished by machine with great precision, the shield will hang upon the upper edge of the band in exact parallelism to the plane of the band edge. The bent-over or hook part of the flange may be spot welded to the band without introducing any strain or probability of causing the band to bow or bulge, this improbability being even greater by virtue of the reenforcing effect of the bend by which the hookformation is obtained.

In conclusion, it may be pointed out that the band structure composed of duplicate sections for each enables all of the sections to be made economically with one pair of dies, and obtains sections which are bent by machine to their desired shape as used. Furthermore the interfitting of ends of the band sections is conducive to economy of material as well as confining the Welding to the ends of the band as distinguished from the prior art overlapping of the strip forming the band at the extended or flat area and welding at that area with its detrimental tendency to cause bulging. The welding of the ends of the band sections in the present invention not only secures the ends together, but secures the band in place on the rods. It follows from the above, that minimum welding is required and that the welding is at a place where there is reenforcement for the thin metal of the band by presence thereat of the rods. In addition to these features, the sections are readily assembled with their upper edges in a common plane and form a long bearing support for the shield 42 mounted thereon. These and other advantages have proven meritorious from the standpoints of manufacture and use.

We claim:

1. A grid structure having apart thereof formed as a band, said band comprising a pair of sections of substantially equal length, the end edge of one section having a butt engagement with the end of the other section, and said sec tions being welded at the area where abutting.

2. A grid structure having a part thereof formed as a band, said band comprising sectionshaving ends formed to interfit Within the limits of the thickness of the material of which the band is made, said sections being welded at the area of the interfitting ends.

3. A grid structure having a part thereof formed as a band and said band providing opposite fiat extended areas and shorter curved areas connecting the flat areas, said band comprising sections of which each section provides one of the said flat areas and part of each of two curved areas.

4. A grid structure having a part thereof formed as a band and said band providing opposite flat extended areas and shorter curved areas connecting the flat areas, said band comprising sections of which each section provides one of the said flat areas and part of each of two curved areas, said sections meeting at said curved areas and welded thereat.

5. A grid structure having a part thereof formed as a band, said band comprising a pair of sections, a pairof supporting rods at opposite sides of the band, and said sections being welded together and to said supporting rods.

6. A grid structure having a part thereof formed as a band, said band comprising a pair of sections with each section in endwise continuation of the other, a pair of supporting rods at opposite sides of the band at the ends of said sections, said section ends all overlapping the said rods in juxtaposition thereto and welded together and to the rod at the overlapping parts of the sections.

7. An electron discharge device having electrodes of which one electrode comprises duplicate sections abutting at end edges, one end of each section having a tongue and the abutting edge of the other section having a notch the size of said tongue and into which said tongue enters when the said sections are caused to abut, and supporting rods next the said tongues and notches, said sections being welded to said rods at the parts thereof having the tongues and notches.

WILLIAM J. KNOCHEL. JAMES H. CONE. 

